This is Europe's mightiest Barbican, 24.4 metres in diameter. Its walls are three meters thick. is topped with seven turrets and has four rows of slitholes... the lower used by artillery, the upper for archers and riflemen. In the past it was was surrounded by a wide, deep moat. The barbican was connected with the Floriana Gate tower by a drawbridge and a walled passage.
Nowadays the 500-year-old fortification serves as a concert hall and theatre.